Memory devices are typically provided as internal, semiconductor, integrated circuits in computers or other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and flash memory. If memory devices are to continue meeting consumer needs, improvements in speed, cost, and size need to continue.
DRAM devices are typically used as the main data memory for computers due to its relatively low cost and high speeds for reading and writing. However, when power is removed, DRAM loses its data. DRAM cells must also be refreshed periodically to keep the data intact.
Flash memory devices have developed into a popular source of non-volatile memory for a wide range of electronic applications. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Common uses for flash memory include personal computers, personal digital assistants (PDAs), digital cameras, and cellular telephones. Program code and system data such as a basic input/output system (BIOS) are typically stored in flash memory devices for use in personal computer systems. Flash memory devices can retain data even after power has been removed and flash memory cells do not require time-consuming refresh operations. Flash memory, however, is substantially more expensive than DRAM and is slow for both read and write operations.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a memory device having the benefits of both non-volatile memory and DRAM devices.